Question

Alaina evaluated 1718+120 and got an answer of 1838. Which statement is true about her answer?

Answer 1

Answer:

Her answer is not correct because the sum cannot be less than either addend.

Answer 2

Answer:

Her answer is not correct because the sum cannot be less than either addend.

The correct answer is $\frac{179}{180}$

Step-by-step explanation:

Given:

The expression to add is given as:

$\frac{17}{18}+\frac{1}{20}$

Alaina got the answer as $\frac{18}{38}$

Let us first try to add the fractions and arrive at the answer.

Taking LCD of 18 and 20, we get LCD = 180

Now, making denominators of each fraction equal to 180 and changing the numerators accordingly.

$=\frac{17\times 10}{18\times 10}+\frac{1\times 9}{20\times 9}\\=\frac{170}{180}+\frac{9}{180}\\=\frac{170+9}{180}=\frac{179}{180}$

Therefore, the result of Alaina is not correct because she got an answer which is less than the fraction $\frac{17}{18}$. But when we add two fractions, the result must be greater than either of the addend.

Therefore, her answer is not correct because the sum cannot be less than either addend.